Sections
Key Equations

Key Equations

speed of sound v=fλ v=fλ
intensity I= P A I= P A
sound intensity I= ( Δp ) 2 2ρ v w I= ( Δp ) 2 2ρ v w
sound intensity level β (dB)=10  log 10 ( I I 0 ) β (dB)=10  log 10 ( I I 0 )
Doppler effect observed frequency (moving source) f obs = f s ( v w v w ± v s ) f obs = f s ( v w v w ± v s )
Doppler effect observed frequency (moving observer) f obs = f s ( v w ± v obs v w ) f obs = f s ( v w ± v obs v w )
beat frequency f B =| f 1 f 2 | f B =| f 1 f 2 |
resonant frequencies of a closed-pipe resonator f n =n v 4L , n=1,3,5... f n =n v 4L , n=1,3,5...
resonant frequencies of an open-pipe resonator f n =n v 2L , n=1,2,3... f n =n v 2L , n=1,2,3...